DESCRIPTION: The molecular mechanisms of microtubule morphogenesis and their regulation are addressed by this application. Specifically, this proposal focuses on Rbl2p, a S. cerevisiae protein involved at some basic level in the pathway from tubulin gene-products to functional microtubules. Rbl2p was identified by this group by its ability to suppress the deleterious effects of overexpression of b-tubulin. It is similar in sequence to murine cofactor A which has also been implicated in microtubule assembly. Other gene-products related to microtubule assembly and/or function will also be examined.